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Biomedical subjects

M Lenzi

Publications and source records attributed to M Lenzi.

At least 109 records · Page 6Linked to original sources
PubMed1983

A microELISA assay to detect anti-liver-specific protein antibodies in the sera of patients with liver diseases.

A microELISA to detect anti-liver-specific protein (LSP) antibodies in human sera is described. Rabbit LSP was used as antigen. Optimal conditions for antigen concentration, serum dilution, substrate incubation time and reproducibility with time were established. The microELISA is specific, as assessed by testing anti-LSP positive sera with another lipoprotein from rabbit plasma (VLDL), although a weak cross-reactivity between LSP and VLDL was observed. The test was applied to patients with HBsAg-positive and -negative chronic active hepatitis (CAH). Ten of 26 (38%) patients were positive for anti-LSP antibodies, in comparison with healthy controls used to determine the threshold of positivity. Such a percentage is comparable with that reported for radioimmunoassay (RIA) procedures.

Antibody Specificity↗
PubMed1983

Binding properties of mechanically and enzymatically isolated hepatocytes for IgG and C3.

The presence of Fc and C3 receptors was studied on mechanically and enzymatically isolated rabbit, mouse and rat hepatocytes as well as on hepatocytes derived from primary cultures. The same cell preparations were used for studying the uptake of an antibody against nuclear antigens. Mechanically isolated hepatocytes were able to bind AIgG and activate complement. However, the same cells were not able to form rosettes with EA or with EAC. Enzymatically isolated hepatocytes did not bind AIgG or activate complement nor did they form rosettes with EA or with EAC. The mechanically isolated cells and the nonviable fraction of the enzymatically isolated cells showed a nuclear fluorescence when incubated with an antibody against nuclear antigens. We conclude that enzymatically isolated hepatocytes lack Fc and C3 binding sites. Furthermore, the damage to the plasma membrane of the non-viable cells allows the penetration of antibodies against intracellular antigens.

Animals↗
PubMed1982

[Brain cortex phospholipids and pituitary gonadotropin incretion (diagnostic use of an acute BC-PL test in secondary amenorrhea of presumably diencephalic origin)].

Bovine brain cortex phospholipids (BC-PL) have a partially dopaminergic effect on the human CNS. This leads to modifications in gonadotropins (FSH, LH and prolactin) pituitary incretion in normal subjects. The Authors have developed an acute test for phospholipids (300 and 600 mg by fast i.v. injection) to be performed in patients suffering from secondary normoprolactinemic amenorrhea possibly of diencephalic origin (hypothesis: hypothalamus function test). In these subjects no change in FSH and LH incretion was observed, whereas blood prolactin levels appeared remarkably reduced. In a small group of patients affected by hyperprolactinemia brain cortex phospholipids produced a more rapid and more marked reduction in blood prolactin (similar to that caused by bromocriptine) in functional conditions in comparison to the organic ones.

Amenorrhea↗
PubMed1980

Smooth-muscle antibodies in children with neuroblastoma.

Smooth-muscle antibodies (SMA) were detected in 16 of 18 (89%) children with neuroblastoma and in 43 of 172 (25%) pediatric hospital patients without malignancies. The SMA were mainly of the IgG class. The most common immunofluorescence pattern was SMA-V (vessel) and titers did not exceed 1:160. Absorption and immunodiffusion tests with action (from rabbit skeletal muscle) showed that the SMA associated with neuroblastoma are mainly directed against actin, although different antigen specificities (myosin, meromyosin) are probably involved in some cases. In both chronic active hepatitis and neuroblastoma, SMA would represent a specific response to intracellular contractile proteins (mainly actin) induced by tissue damage. A feedback role in controlling cellular proliferation has been postulated for experimentally raised SMA. This would be relevant in cases of malignancy.

Antibodies↗
PubMedDate not supplied

Multiple viral/self immunological cross-reactivity in liver kidney microsomal antibody positive hepatitis C virus infected patients is associated with the possession of HLA B51.

Liver Kidney Microsomal autoantibody type 1(LKM1) directed to cytochrome P4502D6 (CYP2D6) characterises autoimmune hepatitis type-2 (AIH-2), but is also found in a proportion of chronic hepatitis C virus (HCV) infected patients, CYP2D6252-271 being a major B- cell autoepitope. Molecular mimicry and immunological cross-reactivity between CYP2D6252-271, HCV polyprotein and the infected cell protein 4 (ICP4) of herpes simplex virus type 1 (HSV-1) have been suggested as triggers for the induction of LKM1, but reactivity and cross-reactivity to the relevant sequences have not been investigated experimentally. CYP2D6252-271 and its viral homologues were constructed and tested by ELISA in the sera of 46 chronically infected HCV patients, 23 of whom were LKM1 positive. Reactivity to the E1 HCV and ICP4 HSV1 mimics was frequently found in HCV infected patients irrespectively of their LKM1 status; viral/self cross-reactivity (as indicated by inhibition studies), however, was present in the only 2 of the 23 LKM1 seropositive HCV patients, who possessed the HLA allotype B51. Our results indicate that in HCV infected patients virus/self cross-reactivity is dependent on a specific immunogenetic background, a finding awaiting confirmation by studies in larger series of patients.

Adult↗